Fourier amplitude of geopotential height
Wave 3 component of the geopotential field of each season at 200hPa.
Mean wave 3 component of geopotential height between 65°S and 35°S
First 4 EOFs derived from the 200hPa geopotential zonal anomaly field between 30°S and 80°S with zonal wave 1 filtered out.
Fourier decomposition by latitude of each EOF.
Monthly mean values for each PC. Colors and shapes divide months into 5 'seasons'.
NO VA. Clústering jerárquico. Cortando en ~0.03 se obtienen 4 clusters, y un 5to separando Abril de ASO por continuidad temporal. Confirma la validez del agrupamiento "a ojo"
Notes:
Making other (still sensible) decisions lead to some differences in clustering. For example, using fields with QS1 and QS2 filtered out puts May closer to April, and December further from JFM. Not surprisingly, a similar result is achieved by using using idealized fields from the reconstructed zonal wave 3 (since higher wavenumbers explain a negligible proportion of the viariance). JFM and ASO (and it's similarity with April), on the other hand, are robust trimesters.
This differences imply that the ZW2 might be have an important role in the variability in May and December.
JJ is a relatively robust grouping but with obviously more heterogeneous than JFM or ASO
Futhermore, removing the linear trend as well as the QS1 field results in a similar classification to the one shown, but the structure of the EOF is slightly different with less separation between wavenumbers (the zonal wave 3 is present in PC1, PC2 and PC3) and a much more asymmetric nature, with higher amplitude anomalies on the western hemisphere than the eastern in the first two PCs and the reverse on the second two. Is it as the wave activity of each hemosphere is separated this way.
Lo anterior justifica el agrupamiento de los meses que viene.
Zonal anomaly of 200hPa geopotential field with zonal wavenumber 1 filtered out. Areas with zonal wind greater than 30 m/s are hatched.
Mean geopotential zonal anomaly with zonal wave 1 filtered out between 65°S and 35°S
Zonal anomaly of 200hPa geopotential field with zonal wavenumber 1 and 2 filtered out. Areas with stationary wave number less than 3 are shaded.
Mean geopotential zonal anomaly with zonal wave 1 and 2 filtered out between 65°S and 35°S
Mean streamfunction.
Mean streamfunction with zonal wave 1 filtered out.
Mean streamfunction with waves 1 and 2 filtered out.
Amplitude of zonal wave 3 for each season defined in the text.
| season | stationarity | MA | AM |
|---|---|---|---|
| DJFM | 0.64 | 35.66 | 23.50 |
| A | 0.62 | 41.66 | 26.23 |
| MJJ | 0.52 | 45.22 | 23.90 |
| ASO | 0.54 | 44.14 | 24.04 |
| N | 0.20 | 37.18 | 6.69 |
Regression between PCs and gh.
Regression between PCs and Psi.
Regression of standarized PC with antarctic sea ice concentrations.